Rawlins-Schellhardt Gas Deliverability Rate Formula
Rawlins-Schellhardt Gas Deliverability Rate calculates gas flow rate for inflow performance workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (C_rs, P_r, P_wf, n_rs) are known and the assumptions behind the cited inflow performance relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, q_g equals 87.209596 MSCF/day.
0.0003
3000
1500
0.8
Inputs
C_rs
MSCF/day/psi^(2n)Rawlins-Schellhardt Deliverability Coefficient
P_r
psiaAverage Reservoir Pressure
P_wf
psiaFlowing Bottom-Hole Pressure
n_rs
dimensionlessRawlins-Schellhardt Deliverability Exponent
Outputs
q_g
Gas Flow Rate
C_rs
Rawlins-Schellhardt Deliverability Coefficient
delta_p2
Pressure-Squared Drawdown
P_r
Average Reservoir Pressure
P_wf
Flowing Bottom-Hole Pressure
n_rs
Rawlins-Schellhardt Deliverability Exponent
Source and review
reviewedPenn State PNG 301. Deliverability Testing, Rawlins-Schellhardt backpressure relationship.
Source